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<title>PTypes: string: constructors/destructors</title>
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<p><a href="../index.html"><img src="title-21.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.1" border="0"></a>
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<p class="hpath"><a href="index.html">Top</a>: <a href="basic.html">Basic types</a>:
<a href="string.html">string</a>: Constructors/destructors</p>
<blockquote>
<pre class="lang">#include <ptypes.h>
class string {
string();
string(const string&);
string(char);
string(const char*);
string(const char*, int);
~string();
}
</pre>
</blockquote>
<p>A string object can be constructed in 5 different ways:</p>
<ul>
<li>
<p> default constructor <span class="lang">string()</span> creates an empty string.</p>
</li>
<li>
<p>copy constructor <span class="lang">string(const string& s)</span> creates
a copy of the given string <span class="lang">s</span>. Actually this constructor
only increments the reference count by 1 and no memory allocation takes place.</p>
</li>
<li>
<p><span class="def">string(char c)</span> constructs a new string consisting
of one character <span class="lang">c</span>.</p>
</li>
<li>
<p><span class="def">string(const char* s)</span> constructs a new string object
from a null-terminated string. If <span class="lang">s</span> is either <span class="lang">NULL</span>
or is a pointer to a null character, an empty string object is created. This constructor
can be used to assign a string literal to a string object (see examples below).</p>
</li>
<li>
<p><span class="def">string(const char* s, int len)</span> copies <span class="lang">len</span>
bytes of data from buffer <span class="lang">s</span> to the newly allocated string
buffer.</p>
</li>
</ul>
<p>Destructor <span class="lang">~string()</span> decrements the reference count
for the given string buffer and removes it from the dynamic memory if necessary.</p>
<p><b>Examples:</b></p>
<blockquote>
<pre>string s1; <span class="comment">// empty string</span>
string s2 = s1; <span class="comment">// copy</span>
string s3 = 'A'; <span class="comment">// single character</span>
string s4 = "ABCabc"; <span class="comment">// string literal</span>
char* p = "ABCabc";
string s5 = p; <span class="comment">// null-terminated string</span>
string s6(p, 3); <span class="comment">// buffer/length</span>
</pre>
</blockquote>
<p class="seealso">See also: <a href="string.operators.html">Operators</a>, <a href="string.typecasts.html">Typecasts</a>,
<a href="string.manipulation.html">Manipulation</a>, <a href="string.conversion.html">Conversion</a></p>
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